Computer Based Models for Disposable Articles, Disposable Article Material, and/or Disposable Article Converting Machines

ABSTRACT

Computer based CAE models for simulating the physical behavior of disposable articles during manufacturing processes.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.11/959,986, filed Dec. 19, 2007, which is hereby incorporated byreference.

FIELD

In general, embodiments of the present disclosure relate to computerbased models for disposable articles. In particular, embodiments of thepresent disclosure relate to computer based CAE models for simulatingthe physical behavior of disposable articles, disposable articlematerial(s), and/or disposable article machines during manufacturingprocesses.

BACKGROUND

Diaper machines can use diaper materials to manufacture diapers. Duringdiaper manufacturing processes, the diaper materials can interact withthe diaper machines and with surrounding air. It can be difficult topredict the physical behavior of the diaper materials as they interactwith the diaper machines and with the surrounding air. As a result, itcan be difficult to predict whether or not a particular diaper machinedesign can successfully process a particular configuration of a diaperor diaper materials.

SUMMARY

However, embodiments of the present disclosure can at least assist inpredicting whether or not a particular diaper machine design cansuccessfully process a particular configuration of a diaper or diapermaterials. The present disclosure includes methods of simulating thephysical behavior of one or more diapers and/or diaper materialsinteracting with diaper machines and moving through surrounding air. Asa result, particular diaper machine designs and particularconfigurations of diapers and/or diaper materials can be evaluated andmodified as computer based models before they are tested as real worldthings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an outside plan view illustrating an exemplary diaper laidout flat.

FIG. 1B is an outside plan view illustrating a folded version of thediaper of the embodiment of FIG. 1A.

FIG. 2A is an outside plan view illustrating a computer based model of aportion of a continuous web of diaper materials, for use in a diapermanufacturing process.

FIG. 2B is an outside plan view illustrating the computer based model ofthe portion of the continuous web of diaper materials of the embodimentof FIG. 2A.

FIG. 3 is a perspective view illustrating the computer based model ofthe portion of the continuous web of diaper materials of the embodimentof FIG. 2B, and a computer based model of a portion of a diaperconverting machine, for use in the diaper manufacturing process.

FIG. 4A is a perspective view illustrating the computer based model ofthe portion of the continuous web of diaper materials of the embodimentof FIG. 2B, the computer based model of the portion of the diaperconverting machine of the embodiment of FIG. 3, and a computer basedmodel of air present in the diaper manufacturing process.

FIG. 4B is a cross-sectional view illustrating the computer based modelof the portion of the continuous web of diaper materials of theembodiment of FIG. 2B, the computer based model of the portion of thediaper converting machine of the embodiment of FIG. 3, and the computerbased model of the air of the embodiment of FIG. 4A.

FIG. 5A is a plan view illustrating a computer based model of anexemplary discrete piece of diaper trim material.

FIG. 5B is a plan view illustrating a computer based model of anexemplary portion of a continuous piece of diaper trim material.

FIG. 6 is a perspective view illustrating the computer based model ofthe portion of the continuous piece of diaper trim material of theembodiment of FIG. 5B, and a computer based model of a portion of a trimremoval apparatus, for use in diaper manufacturing process.

FIG. 7A is a perspective view illustrating the computer based model ofthe portion of the continuous piece of diaper trim material of theembodiment of FIG. 5B, the computer based model of the portion of thetrim removal apparatus of the embodiment of FIG. 6, and a computer basedmodel of air present in the diaper manufacturing process.

FIG. 7B is a cross-sectional view illustrating the computer based modelof the portion of the continuous piece of diaper trim material of theembodiment of FIG. 5B, the computer based model of the portion of thetrim removal apparatus of the embodiment of FIG. 6, and the computerbased model of the air of the embodiment of FIG. 7A.

FIG. 8 is a chart illustrating a method of using computer based modelsof diapers and/or diaper materials, a diaper machine, and air, tosimulate a physical behavior of diapers and/or diaper materials as theyinteract with a diaper machine and with air, in a diaper manufacturingprocess.

DETAILED DESCRIPTION

The present disclosure includes methods of simulating the physicalbehavior of one or more diapers and/or diaper materials interacting withdiaper machines and moving through surrounding air. Embodiments of thepresent disclosure can at least assist in predicting whether or not aparticular diaper machine design can successfully process a particularconfiguration of a diaper and/or diaper materials. As a result,particular diaper machine designs and particular configurations ofdiapers and/or diaper materials can be evaluated and modified ascomputer based models before they are tested as real world things.

Computer aided engineering (CAE) is a broad area of applied science inwhich technologists use software to develop computer based models ofreal world things. The models can be used to provide various informationabout the physical behavior of those real world things, under certainconditions and/or over particular periods of time. With CAE, theinteractions of the computer based models are referred to assimulations. Sometimes the real world things are referred to as aproblem and the computer based model is referred to as a solution.

There are several major categories of CAE. Finite element analysis (FEA)is a major category of CAE, in which models of mechanical componentsand/or assemblies are used to predict stress, strain and othermechanical behaviors. Computation fluid dynamics (CFD) is another majorCAE category, in which models of fluids (e.g. liquids and/or gases) areused to predict pressure, flow, temperature, and other fluid and/orthermal properties. Still another major category of CAE is fluidstructure interaction (FSI), which models the physical behavior offluids in relation to solid objects. There are also a number of othercategories of CAE.

Some aspects of CAE can also relate to various Computer Aidedtechnologies, sometimes collectively referred to as CAx. CAx includes anumber of technologies, such as Computer Aided Design (CAD), ComputerAided Manufacturing (CAM), and Knowledge Based Engineering (KBE).

Commercially available software can be used to conduct CAE. Abaqus, fromSIMULIA in Providence, R.I., and LSDyna from Livermore SoftwareTechnology Corp. in Livermore, Calif., are examples of commerciallyavailable FEA software. Fluent, from ANSYS, Inc, in Canonsburg, Pa., andFlow3D, from Flow Science, Inc. in Santa Fe, N. Mex. are examples ofcommercially available CFD software. LSDyna is also an example of FSIsoftware. CAE software can be run on various computer hardware, such asa personal computer, a minicomputer, a cluster of computers, amainframe, a supercomputer, or any other kind of machine on whichprogram instructions can execute to perform CAE.

CAE software can be applied to a number of real world things, such asdisposable articles. The term disposable articles includes diapers,feminine hygiene products, and other disposable articles.

A diaper can be referred to in various alternate ways. As examples, adiaper can sometimes be referred to as an absorbent article, absorbentbriefs, an absorbent product, an absorbent item, an absorbent garment,an absorbent pant, an absorbent panty, an absorbent undergarment,absorbent underwear, a wearable absorbent article, a disposableabsorbent article, a disposable wearable absorbent article, incontinencebriefs, an incontinence garment, an incontinence napkin, incontinencepants, an incontinence product, an incontinence towel, an incontinenceundergarment, a nappy, a napkin, a pant, pants, a disposable pant,disposable pants, a training pant, training pants, a pull-up, pull-ups,etc. A diaper can be configured for use by various human wearers, suchas infants and incontinent persons. Throughout the present disclosure,the terms diaper and diapers are intended to refer to one or more of anyof these and all other forms of a diaper, unless otherwise stated.

CAE software can also be applied to diaper materials. Throughout thepresent disclosure, the terms diaper material and diaper materials areintended to refer to one or more diapers in any state of formation, fromone or more starting materials, to one or more partially formed diapers,to one or more individual, finished diapers, and one or more diapers inany state or states in between.

CAE can be used to design, simulate, and/or evaluate diaper materials,their structures and compositions, as well as their performancecharacteristics, such as swelling and deformation. CAE can also be usedto design, simulate, and/or evaluate diaper features or products. Asexamples, CAE can be used to simulate the performance of various aspectsof diaper products, such as fluid transport and storage, thermal andmechanical performance, fluid structure interactions, product packagingand dispensing, and gluing performance. CAE can also be used to simulatethe fit of a diaper product on a wearer.

As additional examples, CAE can be used to design, simulate, and/orevaluate diaper machines and/or diaper manufacturing processes. CAE canbe used to simulate mechanical aspects of diaper manufacturing processesrelated to cutting, material deformation, bonding, and material productinteractions. CFI) can be used to simulate air flow in diaper machinesas well as liquid flow and/or transport in diaper manufacturingprocesses. CAE can also be used to simulate and/or evaluate thefeasibility of diaper manufacturing processes, the reliability of diapermachines, and potential quality issues with diaper materials.

FSI can be used to simulate and/or evaluate the transport of particlesin air in diaper manufacturing processes. For example, FSI can be usedto design, simulate, and/or evaluate diaper manufacturing processes inwhich one or more absorbent materials are conveyed through a diapermachine and added to a web of diaper materials.

FSI can also be used to simulate and/or evaluate the transport and/ordeformation of sheet-like diaper materials as they interact with diapermachines and with air in diaper manufacturing processes. As an example,FSI can be used to simulate and/or evaluate a physical behavior of a webof diaper materials interacting with a diaper converting machine andmoving through air, as described in connection with the embodiments ofFIGS. 1A-4B, and 8. As another example, FSI can be used to simulateand/or evaluate a physical behavior of diaper trim materials interactingwith a trim removal apparatus and moving through air, as described inconnection with the embodiments of FIGS. 5A-8.

CAE software can be similarly applied to aspects of various femininehygiene products, such as liners, feminine liners, hygiene liners,hygienic liners, panty liners, sanitary liners, pads, feminine pads,hygiene pads, hygienic pads, panty pads, sanitary pads, napkins,feminine napkins, hygiene napkins, hygienic napkins, panty napkins,sanitary napkins, feminine hygiene articles, feminine sanitary articles,etc.

CAB software can also be similarly applied to aspects of some otherdisposable articles, such as paper towels, bathroom tissues, facialtissues, wipes, and cleaning pads, etc.

FIG. 1A is an outside plan view illustrating an exemplary diaper 110laid out flat. The diaper 110 includes a chassis 111, side edges 114,end edges 115, an absorbent core 112, and ears 113. The ears 113 includefasteners, so the diaper 110 is configured as a fastenable diaper. Thediaper also has a lateral centerline 121, a longitudinal centerline 122,an overall length 123, an overall width 124, and fold lines 116. Duringthe diaper manufacturing process, laterally outboard portions of thediaper 110 can be folded inward along the fold lines 116, as describedin connection with the embodiment of FIG. 1B.

FIG. 1B is an outside plan view illustrating a folded version of theexemplary diaper 110 of the embodiment of FIG. 1A. In FIG. 1B, laterallyoutboard portions of the diaper 110 are folded along the fold lines 116onto an inside of the diaper 110. The folded diaper 110 has folded edges117 and a folded width 125.

The exemplary diaper 110 is not intended to illustrate all details of adiaper. The exemplary diaper 110 is also not intended to limitembodiments of the present disclosure. Instead, the exemplary diaper 110is intended to illustrate at least some of the diaper features on onekind of diaper, which can be incorporated into a computer based model ofa portion of a continuous web of diaper materials, as described in theembodiment of FIG. 2A.

FIG. 2A is an outside plan view illustrating a computer based model 230of a portion of a continuous web of diaper materials 231, for use in adiaper manufacturing process. During the diaper manufacturing process,the portion of the continuous web of diaper materials 231 moves with avelocity 227 in a machine direction 228. The portion of the continuousweb of diaper materials 231 includes a sheet-like series of partiallyformed diapers 232-1 through 232-N, where “N” is any positive integer,in the embodiment of FIG. 2A, the web of diaper materials 231 includesfour partially formed diapers.

The partially formed diapers 232-1 through 232-N are connected togetherend-to-end. For clarity, separation lines 233 illustrate end edges to beformed downstream in the diaper manufacturing process. Each of thepartially formed diapers 232-1 through 232-N can be a partially formedversion of the diaper 110 of the embodiment of FIG. 1A. In theembodiment of FIG. 2A, each of the partially formed diapers 232-1through 232-N includes a chassis, an absorbent core, and ears withfasteners.

The model 230 of the portion of the continuous web of diaper materials231 includes a leading edge 241, a middle portion 244, and a trailingedge 245. The leading edge 241 corresponds with an end edge of thediaper 232-N. The trailing edge 245 corresponds with an end edge of thediaper 232-1. The model 230 also includes tensions resulting fromtensioning forces 247 applied to the leading edge 241 and the trailingedge 245.

In various embodiments, a computer based model of diaper materials caninclude any number of partially formed diapers, including portions ofdiapers. For example, in a computer based model, a continuous web ofdiaper materials can include a leading edge and/or a trailing edge,which may not correspond with an end edge of a diaper. In someembodiments, a computer based model of diapers and/or diaper materialscan include partially or completely formed diapers with any number ofany features, such as waistbands, leg bands, leg cuffs, absorbent coreassemblies, etc. A computer based model of a diaper and/or diapermaterials can, in some embodiments, include any kind of diaper, such asa fastenable type diaper or a preformed pant-type diaper.

FIG. 2B is a plan view illustrating the computer based model 230 of theportion of the continuous web of diaper materials 231, of the embodimentof FIG. 2A. The computer based model 230 is illustrated as broken, toillustrate further details. The portion of the continuous web of diapermaterials 231 includes the sheet-like series of partially formed diapers232-1 through 232-N. During the diaper manufacturing process, theportion of the continuous web of diaper materials 231 moves with avelocity 227 in a machine direction 228. The portion of the continuousweb of diaper materials 231 also includes fold lines 216 and alongitudinal centerline 222, which correspond with the folds lines andthe longitudinal centerlines of each of the partially formed diapers232-1 through 232-N.

The model 230 of the portion of the continuous web of diaper materials231 can be created by using FSI software. The model 230 can be createdby putting in dimensions and material properties for the portion of thecontinuous web of diaper materials 231, generating a mesh, definingboundary conditions for the model 230, and defining interactions betweenparts of the diaper materials and other parts and/or models. By doingso, the computer based model 230 can be configured to accuratelysimulate the physical behavior of a real world continuous web of diapermaterials.

The portion of the continuous web of diaper materials 231 can beconfigured with dimensions that are similar to or the same as dimensionsof a real world continuous web of diaper materials. These dimensions canbe determined by measuring real world samples of diaper materials, byusing accepted values for known materials, and/or by estimation. Valuesfor the length, width, thickness, and/or other dimensions of thechassis, core, ear, fastener and other parts of the partially formeddiapers 232-1 through 232-N can be put into FSI software.

Some or all of the portion of the continuous web of diaper materials 231can be configured with material properties that are similar to or thesame as material properties of a real world continuous web of diapermaterials. These material properties can be determined by measuring realworld samples of diaper materials, by using accepted values for knownmaterials, and/or by estimation. Values for the tensile strength,bending behavior, density and/or other mechanical properties of thechassis, core, ear, fastener and other parts of the partially formeddiapers 232-1 through 232-N can be put into the FSI software. As anexample, material property values for the middle portion 244 can be putinto the FSI software so that the middle portion 244 can be configuredas a flexible middle portion.

In various embodiments, a computer based CAE model can include one ormore material properties that differ from material properties of thereal world thing, in order for the overall model to account for inherentlimitations of the model and/or to more accurately represent the overallphysical behavior of the real world thing, as will be understood by oneof ordinary skill in the art. In various embodiments of the model 230,some of the portion of the continuous web of diaper materials 231 can beconfigured with one or more material properties that differ frommaterial properties of a real world continuous web of diaper materials,in order for the overall model 230 to account for inherent limitationsof the model 230 and/or to more accurately represent the overallphysical behavior of a real world continuous web of diaper materials.For example, the model 230 is limited in that it represents only aportion of a continuous web. The model 230 of the portion 231 has endsedges, while a real world web of diaper materials would be continuous asit enters a diaper machine. As a result, the model 230 has an inherentlimitation in that the portion 231 is not connected to upstream and/ordownstream portions of a web as a real world continuous web of diapermaterials would be.

If in the model 230, an end edge of the portion of the continuous web ofdiaper materials 231 is configured with material properties that aresimilar to material properties of a real world continuous web of diapermaterials, so that the end edge is flexible, then, during the simulationof the model 230, the end edge may tend to distort, bend, and/or curl,so that the edge may not completely accurately represent the physicalbehavior of a real world continuous web of diaper materials.

In order to address this difficulty, in a model of a portion of acontinuous web of diaper materials, a leading edge and/or a trailingedge can include one or more portions configured with materialproperties that differ from material properties of a real worldcontinuous web of diaper materials. These differing material propertiescan effectively represent physical constraints that would be provided byupstream and/or downstream portions of a real world continuous web ofdiaper materials. Specifically, the one or more portions can beconfigured with differing material properties to be sufficiently rigidso as to resist distorting, bending and/or curling. Any part or parts orall of an end edge can be configured to include one or more rigidportions,

In the embodiment of FIG. 2B, the leading edge 241 includes a middleportion configured to be a rigid portion 242. The rigid middle portion242 is substantially centered on the longitudinal centerline 222 andextends laterally outward from the longitudinal centerline 222 to aboutthe fold lines 216. In various embodiments, the rigid middle portion 242may not extend all the way out to the fold lines 216. Since the rigidmiddle portion 242 is laterally inboard to the fold lines 216, laterallyoutboard portions of the portion of the continuous web of diapermaterials 231 can be folded along the fold lines 216 onto an inside ofthe diaper materials, as described in connection with the embodiments ofFIGS. 1A-4B. The leading edge 241 also includes flexible outer portions243, which are laterally outboard from the rigid middle portion 242. Theflexible outer portions 243 can be configured with material propertiesthat are similar to or the same as material properties of correspondingportions of a real world continuous web of diaper materials, which mayor may not be same the as the material properties of other portions ofthe chassis. Also, in the embodiment of FIG. 2B, the trailing edge 241is configured to be a rigid trailing edge 242.

The model 230 of the portion of the continuous web of diaper materials231 can also include a mesh. A mesh is a collection of small, connectedpolygon shapes that define elements in a CAE computer based model. Amesh can be generated by using commercially available meshing software.In some embodiments, the type of mesh and/or the size of mesh elementscan be controlled with user inputs into the meshing software, as will beunderstood by one of ordinary skill in the art. The mesh for the portionof the continuous web of diaper materials 231 can be generated usingcommercially available meshing software. For clarity, a mesh is notillustrated in the embodiment of FIGS. 2A and 2B.

The model 230 of the portion of the continuous web of diaper materials231 can also include boundary conditions, Boundary conditions aredefined physical factors which can interact with parts of a CAE computerbased model. Examples of boundary conditions include forces, pressures,velocities, and physical constraints, each of which can be assigned aparticular magnitude and direction and/or can be applied to a specificlocation within the model. Boundary conditions can act on the model invarious ways, to move, constrain, and/or deform one or more parts in themodel. Boundary conditions can be determined by observing, measuring,analyzing and/or estimating real world physical factors which caninteract with a real world continuous web of diaper materials. Invarious embodiments, a computer based CAE model can include one or moreboundary conditions that differ from real world physical constraints, inorder for the overall model to account for inherent limitations of themodel and/or to more accurately represent the overall physical behaviorof the real world thing, as will be understood by one of ordinary skillin the art. Boundary conditions for the portion of the continuous web ofdiaper materials 231 can be put into the FSI software.

The model 230 includes boundary conditions of forces and velocities. Theportion of the continuous web of diaper materials 231 includes thevelocity 227 in the machine direction which is applied to the entireweb, to simulate the real world movement of a continuous web of diapermaterials in a diaper machine. In addition, the leading edge 241 and/orthe trailing edge 245 can be directed along a particular pathway, tosimulate physical constraints within a diaper machine.

The portion of the continuous web of diaper materials 231 also includestensions resulting from the tensioning forces 247, which can bedistributed along end edges of the web, to simulate the real worldtensions in a continuous web of diaper materials in a diaper machine.The tensioning forces 247 distributed along the leading edge 241 can beabout equal or exactly equal in magnitude to the tensioning forces 247distributed along the trailing edge 245. The tensioning forces 247distributed along the leading edge 241 can be directed generally in themachine direction 228, while the tension forces 247 distributed alongthe trailing edge 245 can be directed generally opposite to the machinedirection 228. In various embodiments, some or all of the forces and/orvelocities included in the model 230 can be determined in one or moreprior simulations and subsequently applied to the model 230.

The model 230 of the portion of the continuous web of diaper materials231 can also include defined interactions between its parts and/or withpart or all of one or more other CAE computer based models. The model230 of the portion of the continuous web of diaper materials 231 isdefined so that all of its parts can physically interact with eachother. The model 230 of the portion of the continuous web of diapermaterials 231 is also defined so that it can physically interact withall parts of a computer based model 350 of a portion of a diaperconverting machine 351, as described in connection with the embodimentof FIG. 3. The model 230 of the portion of the continuous web of diapermaterials 231 is further defined so that it can also physically interactwith all parts of a computer based model 470 of air 471, 473, asdescribed in connection with the embodiment of FIGS. 4A and 4B. Invarious embodiments, one or more computer based CAE models can includeone or more defined interactions that differ from real world physicalinteractions, in order to account for inherent limitations in the modelsand/or to more accurately represent the overall physical behaviors ofthe real world things, as will be understood by one of ordinary skill inthe art. These interactions can be defined in the FSI software.

FIG. 3 is a perspective view illustrating the computer based model 230of the portion of the continuous web of diaper materials 231 of theembodiment of FIG. 2A, and a computer based model 350 of a portion of adiaper converting machine 351, for use in the diaper manufacturingprocess. The diaper converting machine is configured to convert acontinuous web of diaper materials into individual diapers. The portionof the diaper converting machine 351 includes a roller 352 with a rollercontact surface 353 and a roller axis 354. The portion of the diaperconverting machine 351 also includes a folding apparatus 355 with afolding contact surface 356.

The roller contact surface 353 and the folding contacting surface 356are surfaces configured for contact with the computer based model 230 ofthe portion of the continuous web of diaper materials 231. The roller352 is configured so that the portion of the continuous web of diapermaterials 231 can be conveyed over the roller 352. The folding apparatus355 is configured so that the portion of the continuous web of diapermaterials 231 can be folded by the folding apparatus 355.

In various embodiments, a computer based model of a diaper convertingmachine can include any number of any kind of machine part or apparatusknown in the art. For example, the diaper converting machine can includeone or more rollers, folding apparatuses, bonding apparatuses, cuttingapparatuses, etc.

The model 350 of the portion of the diaper converting machine 351 can becreated by using FSI software. The model 350 can be created by puttingin dimensions and material properties for the portion of the diaperconverting machine 351, generating a mesh, defining boundary conditionsfor the model 350, and defining interactions between parts of theportion of the diaper converting machine 351 and other parts or models.By doing so, the computer based model 350 can be configured toaccurately simulate the physical behavior of a real world diaperconverting machine.

The portion of the diaper converting machine 351 can have dimensionsthat are similar to or the same as dimensions of a real world diaperconverting machine. These dimensions can be determined by measuring realworld parts of a diaper converting machine, by using documenteddimensions for known parts, and/or by estimation. Values for the length,width, thickness, and/or other dimensions of the roller 352 and thefolding apparatus 355 can be put into FSI software.

The portion of the diaper converting machine 351 can have materialproperties that are similar to or the same as material properties of areal world diaper converting machine. These material properties can bedetermined by measuring real world parts of a diaper converting machine,by using accepted values for known materials, and/or by estimation.Values for the mass, strength, coefficient of friction, and/or othermechanical properties of the roller 352 and the folding apparatus 355can be put into the FSI software. As examples, material property valuescan be put into the FSI software so that the roller contact surface 353has a coefficient of friction of about 1.0, and the folding contactingsurface 356 has a coefficient of friction of about 0.1. In variousembodiments, material property values for other coefficients of frictioncan also be used.

The model 350 of the portion of the diaper converting machine 351 canalso include a mesh of machine elements which can be generated by usingcommercially available meshing software. In some embodiments, the sizeof these machine elements can be defined with user inputs into the meshsoftware. As an example, the size of machine elements for the portion ofthe diaper converting machine 351 can be defined such that substantiallyall of the machine element lengths are greater than or equal to about 1millimeter and less than or equal to about 10 millimeters. Also as anexample, the machine elements can be defined such that substantially allof the machine element lengths are about 5 millimeters. In variousembodiments, user inputs for other machine element lengths can also beused. For clarity, the mesh is not illustrated in the embodiment of FIG.3.

The model 350 of the portion of the diaper converting machine 351 canalso include boundary conditions. The model 350 includes boundaryconditions of physical constraints. The roller 352 is physicallyconstrained by boundary conditions to rotate about the roller axis 354.The roller axis 354 is physically constrained by boundary conditions tomaintain a fixed location and orientation in space, despite forcesacting upon it. The folding apparatus 355 is also physically constrainedby boundary conditions to maintain a fixed location and orientation inspace, despite forces acting upon it. Boundary conditions for the roller352 and the folding apparatus 355 can be put into the FSI software.

The model 350 of the portion of the diaper converting machine 351 canalso include defined interactions between its parts and/or with part orall of one or more other CAE computer based models. The model 350 of theportion of the diaper converting machine 351 is defined so that all ofits parts can physically interact with each other. The model 350 of theportion of the diaper converting machine 351 is also defined so that itcan physically interact with all parts of the computer based model 230of the portion of the continuous web of diaper materials 231, asdescribed in connection with the embodiment of FIGS. 2A-2B. The model350 of the portion of the diaper converting machine 351 is also definedso that it can physically interact with all parts of a computer basedmodel 470 of air 471, 473, as described in connection with theembodiment of FIGS. 4A and 4B. These interactions can be defined in theFSI software.

FIG. 4A is a perspective view illustrating the computer based model 230of the portion of the continuous web of diaper materials 231 of theembodiment of FIG. 2A, the computer based model 350 of the portion ofthe diaper converting machine 351 of the embodiment of FIG. 3, and acomputer based model 470 of air 471, 473 present in the diapermanufacturing process. The model 470 includes a first volume of air 471and a second volume of air 473. For clarity, air is illustrated astransparent, throughout the present disclosure.

The first volume of air 471 completely surrounds the portion of thecontinuous web of diaper materials 231 and completely surrounds theportion of the diaper converting machine 351. In various embodiments,the first volume of air 471 may surround a portion or substantially allof the portion of the continuous web of diaper materials 231 and/or aportion or substantially all of the portion of the diaper convertingmachine 351. The second volume of air 473 completely surrounds the firstvolume of air 471. In various embodiments, the second volume of air 473may surround a portion or substantially all of the first volume of air471. In some embodiments, the first volume of air 471 and/or the secondvolume of air 473 can include a number of smaller volumes of air.

FIG. 4B is a cross-sectional view along section line 4B-4B in FIG. 4A,illustrating the computer based model 230 of the portion of thecontinuous web of diaper materials 231 of the embodiment of FIG. 2A, thecomputer based model 350 of the portion of the diaper converting machine351 of the embodiment of FIG. 3, and the computer based model 470 of theair 471, 473 of the embodiment of FIG. 4A.

The first volume of air 471 can have various dimensions, which candetermine how much of the portion of the continuous web of diapermaterials 231 and how much of the portion of the diaper convertingmachine 351 are surrounded by the first volume of air. The second volumeof air 471 can also have various dimensions, which can determine howmuch of the first volume of air 471 is surrounded by the second volumeof air 473. While the first and second volumes of air 471, 473 areillustrated as rectilinear shapes in the embodiment of FIGS. 4A and 4B,the volumes can also take different shapes. Dimensions for the firstvolume of air 471 and for the second volume of air 473 can be put intoFSI software.

The first volume of air 471 and the second volume of air 473 can eachhave material properties that are similar to or the same as materialproperties of real world air in and/or around a diaper convertingmachine. These material properties can be determined by measuring realworld air in and/or around a diaper converting machine, by usingaccepted values for air, and/or by estimation. Values for pressure,temperature, and/or other gaseous properties for the first volume of air471 and for the second volume of air 473 can be put into the FSIsoftware.

In various embodiments, the second volume of air 473 can be configuredat a particular constant pressure that is about equal to an atmosphericpressure (e.g. about 100 kPa), to simulate the surrounding atmosphere.The first volume of air 471 can, in some embodiments, be configured toallow pressure variations, to simulate local changes in pressureproximate to the portion of the continuous web of diaper materials 231and/or to the portion of the diaper converting machine 351.

The first volume of air 471 and the second volume of air 473 can alsoeach include a mesh of air elements which can be generated by usingcommercially available meshing software. In some embodiments, the sizeof these air elements can be defined with user inputs into the meshsoftware. As an example, the size of air elements for the first volumeof air 471 and/or the second volume of air 473 can be defined such thatsubstantially all of the air element lengths are less than or equal toabout two times the machine element lengths of substantially all of themachine elements of the model 350 of the portion of the diaperconverting machine 351. In various embodiments, user inputs for otherair element lengths can also be used. For clarity, the mesh is notillustrated in the embodiment of FIGS. 4A and 4B.

The first volume of air 471 and the second volume of air 473 can eachalso include boundary conditions. The first volume of air 471 and thesecond volume of air 473 each include boundary conditions of physicalconstraints. The first volume of air 471 and the second volume of air473 are each physically constrained by boundary conditions to maintain afixed location and orientation in space, despite forces acting upon it.Boundary conditions for the first volume of air 471 and the secondvolume of air 473 can be put into the FSI software.

The first volume of air 471 and the second volume of air 473 can eachalso include defined interactions with each other and/or with part orall of one or more other CAE computer based models. The first volume ofair 471 is defined to allow air exchanges 472 with the second volume ofair 473, and vice versa, to simulate the real world movement of air. Thefirst volume of air 471 and the second volume of air 473 are eachdefined so that they can each physically interact with all parts of thecomputer based model 230 of the continuous web of diaper materials 231,as described in connection with the embodiment of FIGS. 2A-2B. The firstvolume of air 471 and the second volume of air 473 are also each definedso that they can each physically interact with all parts of the computerbased model 350 of the diaper converting machine 351, as described inconnection with the embodiment of FIGS. 4A and 4B. These interactionscan be defined in the FSI software.

FSI software can be used to simulate a physical behavior of the model230 of the portion of the continuous web of diaper materials 231interacting with the model 350 of the portion of the diaper convertingmachine 351 and moving through the model 470 of the air 471, 473. As aresult, particular designs of a diaper converting machine and particularconfigurations of diapers and/or diaper materials can be evaluated andmodified as computer based models before they are tested as real worldthings. FSI software can be similarly applied to simulate a physicalbehavior of models of part or all of one or more other disposablearticles interacting with models of part or all of one or more machinesfor manufacturing such articles, and moving through a model of air.

FIG. 5A is a plan view illustrating a computer based model 538 of anexemplary discrete piece of diaper trim material 518. FIG. 5B is a planview illustrating a computer based model 539 of an exemplary portion ofa continuous piece of diaper trim material 519. The discrete piece ofdiaper trim material 518 and the portion of the continuous piece ofdiaper trim material 519 can be any kind of one or more materials, suchas a film and/or a nonwoven. Each of the models 538 and 539 can becreated by using FSI software. Each of the models 538 and 539 can becreated, as described above, by putting in dimensions and materialproperties for the diaper trim material 518 or 519, generating a mesh,defining boundary conditions for the model 538 or 539, and defininginteractions between parts of the diaper trim material 519 or 519 andother parts or models. By doing so, each of the computer based models538 and 539 can be configured to accurately simulate the physicalbehavior of a real world diaper trim material.

FIG. 6 is a perspective view illustrating the computer based model 539of the portion of the continuous piece of diaper trim material 519 ofthe embodiment of FIG. 5B, and a computer based model 660 of a portionof a trim removal apparatus 661, for use in a diaper manufacturingprocess. The model 660 includes a portion of a conveyor 662 and aportion of a trim removal apparatus 661. The portion of the trim removalapparatus 661 includes a nozzle 663 with a nozzle entrance 664 and anozzle exit 665. The nozzle entrance 664 is configured with a particularsize and shape and is oriented above the portion of the conveyor 662.The portion of the continuous piece of diaper trim material 519 rests onthe portion of the conveyor 662. During the diaper manufacturingprocess, the portion of the conveyor 662 moves with a velocity 667 in aconveyor direction 668 so that the portion of the continuous piece ofdiaper trim material 519 passes below the nozzle entrance 664. The trimremoval apparatus 661 is configured to physically transport the portionof the continuous piece of diaper trim material 519 through the nozzleentrance 664 using a vacuum. In various embodiments, a trim removalapparatus can be similarly configured to physically transport a discretepiece of diaper trim material.

The model 660 can be created, as described above, by putting indimensions and material properties for the trim removal apparatus 661,generating a mesh, defining boundary conditions for the model 660, anddefining interactions between parts of the trim removal apparatus 661and other parts or models. By doing so, the computer based model 660 canbe configured to accurately simulate the physical behavior of a realworld trim removal apparatus.

FIG. 7A is a perspective view illustrating the computer based model 539of the portion of the continuous piece of diaper trim material 519 ofthe embodiment of FIG. 5B, the computer based model 660 of the portionof the trim removal apparatus 661 of the embodiment of FIG. 6, and acomputer based model 775 of air present in the diaper manufacturingprocess. The model 775 includes a first volume of air 776, a secondvolume of air 778, and a third volume of air 779. FIG. 7A alsoillustrates the portion of the conveyor 662.

The first volume of air 776 completely surrounds the portion of thecontinuous piece of diaper trim material 519 and completely surroundsthe portion of the trim removal apparatus 661. In various embodiments,the first volume of air 776 may surround a portion or substantially allof the portion of the continuous piece of diaper trim material 519and/or a portion or substantially all of the portion of the trim removalapparatus 661. The second volume of air 778 completely surrounds thefirst volume of air 776. In various embodiments, the second volume ofair 778 may surround a portion or substantially all of the first volumeof air 776. The third volume of air 779 completely covers the nozzleexit 665. In various embodiments, the third volume of air 779 may coverand/or surround a portion or substantially all of the nozzle exit 665.In some embodiments, the first volume of air 776 and/or the secondvolume of air 778 and/or the third volume of air 779 can include anumber of smaller volumes of air.

FIG. 7B is a cross-sectional view along section line 7B-7B in FIG. 7A,illustrating the computer based model 539 of the portion of thecontinuous piece of diaper trim material 519 of the embodiment of FIG.5B, the computer based model 660 of the portion of the trim removalapparatus 661 of the embodiment of FIG. 6, and the computer based model775 of the air 776, 778, 779 of the embodiment of FIG. 7A.

Each of the volumes of air 776, 778, 779 can have various dimensions andshapes, which can determine the degree to which the first volume cansurround and/or cover other particular models or parts of models.Dimensions for the first volume of air 776, the second volume of air778, and the third volume of air 7779 can be put into FSI software.Values for pressure, temperature, and/or other gaseous properties forthe volumes of air 776, 778, 779 can also be put into the FSI software.

In various embodiments, the second volume of air 778 can be configuredat a particular constant pressure that is about equal to an atmosphericpressure e.g. about 100 kPa), to simulate the surrounding atmosphere.The first volume of air 776 can, in some embodiments, be configured toallow pressure variations, to simulate local changes in pressureproximate to the portion of the continuous piece of diaper trim material519 and/or to the portion of the trim removal apparatus 661.

The third volume of air 779 can be configured at a second pressure thatis less than the atmospheric pressure, in order to simulate a partialvacuum. The second pressure can, in various embodiments, be constant orvariable.

Each of the volumes of air 776, 778, 779 can also include a mesh of airelements which can be generated, as described above, by usingcommercially available meshing software. Each of the volumes of air 776,778, 779 can also include boundary conditions, physically constrainingthe volume to maintain a fixed location and orientation in space,despite forces acting upon it. These boundary conditions can be put intothe FSI software.

Each of the volumes of air 776, 778, 779 can also include definedinteractions with each other and/or with part or all of one or moreother CAE computer based models. The first volume of air 776 is definedto allow air exchanges 777 with the second volume of air 778, and viceversa, to simulate the real world movement of air. The first volume ofair 776 and the second volume of air 778 are each defined so that theycan each physically interact with all parts of the computer based model539 of the portion of the continuous piece of diaper trim material 519,as described in connection with the embodiment of FIGS. 7A-7B. Theseinteractions can be defined in the FSI software.

FSI software can be used to simulate a physical behavior of the model539 of the portion of the continuous piece of diaper trim material 519interacting with the model 660 of the portion of the diaper trim removalapparatus 661 and moving through the model 775 of the air 776, 778, 779.As a result, particular designs of a diaper trim removal apparatus andparticular configurations of diaper trim material can be evaluated andmodified as computer based models before they are tested as real worldthings. FSI software can be similarly applied to simulate a physicalbehavior of models of discrete or continuous trim pieces of otherdisposable articles interacting with models of part or all of trimremoval apparatuses, and moving through a model of air.

FIG. 8 is a chart illustrating a method 880 of using computer basedmodels of diapers and/or diaper materials, a diaper machine, and air, tosimulate a physical behavior of diapers and/or diaper materials as theyinteract with a diaper machine and with air, in a diaper manufacturingprocess. The method 880 includes a first step 881 of creating a computerbased model of a diaper and/or diaper materials. As an example, thecomputer based model in the first step 881 can be the computer basedmodel 230 of the portion of the continuous web of diaper materials 231,of the embodiments of FIGS. 2A-4B, for use in a diaper manufacturingprocess. As another example, the computer based model in the first step881 can be the computer based model 538 of the discrete piece of diapertrim material 518, of the embodiment of FIG. 5A, or the computer basedmodel 539 of the portion of the continuous piece of diaper trim material519, of the embodiments of FIGS. 5B-7B, for use in a diapermanufacturing process. In various embodiments, the computer based modelof the first step 881 can be a computer based model of any number and/oramount of any kind of diaper and/or diaper materials, in any state offormation, with any number of any kind of diaper features, as describedherein.

The method 880 includes a second step 882 of creating a computer basedmodel of a diaper machine. As an example, the computer based model of adiaper machine in the second step 882 can be the computer based model350 of the portion of the diaper converting machine 351, of theembodiments of FIGS. 3-4B, for use in a diaper manufacturing process. Asanother example, the computer based model of a diaper machine in thesecond step 882 can be the computer based model 660 of the portion ofthe trim removal apparatus 661, of the embodiments of FIGS. 6-7B, foruse in a diaper manufacturing process. In various embodiments, thecomputer based model of the second step 882 can be a computer basedmodel of any portion of any kind of machine for any kind of function ina diaper manufacturing process, as described herein.

The method 880 includes a third step 883 of creating a computer basedmodel of air. As an example, the computer based model of air in thethird step 883 can be the computer based model 470 of the air 471, 473of the embodiment of FIGS. 4A-4B. As another example, the computer basedmodel of air in the third step 883 can be the computer based model 775of the air 776, 778, 779 of the embodiment of FIGS. 7A-7B. In variousembodiments, the computer based model of the third step 775 can be acomputer based model of one or more volumes of air, as described herein.

In some embodiments of a method of simulating a physical behavior of adiaper and/or diaper materials in a diaper manufacturing process, thethird step 883 may be omitted. For example, in circumstances where theeffects of air on a diaper or diaper materials are known to benegligible, it may not be necessary to create and use a computer basedmodel of air in the simulation. As another example, in preliminarysimulations focused on basic interactions between the diaper and/ordiaper materials and the diaper machine, it also may not be necessary tocreate and use a computer based model of air in the simulation.

Although the first step 881, the second step 882, and the third step 883are described in numerical order in the present disclosure, any of thesesteps can be performed in any order, and/or at overlapping times, and/orat the same time, as will be understood by one of ordinary skill in theart.

The method 880 includes a fourth step 884 of simulating the interactionbetween the models. The fourth step 884 includes simulating theinteraction between: the computer based model of the diaper and/ordiaper materials from the first step 881; the computer based model ofthe diaper machine from the second step 882; and the computer basedmodel of the air from the third step 883. Prior to or during the fourthstep 884, the models to be interacted can be brought together.

In an embodiment of the present disclosure, the simulation of the fourthstep 884 can simulate a physical behavior of the model 230 of theportion of the continuous web of diaper materials 231 interacting withthe model 350 of the portion of the diaper converting machine 351 andmoving through the model 470 of the air 471, 473, during a particularperiod of time. The simulation of the fourth step 884 can, in variousembodiments, include simulating the physical behavior of the model 230of the portion of the continuous web of diaper materials 231 beingfolded by the folding apparatus 355, during a particular period of time.The simulation of the fourth step 884 can, in some embodiments, includesimulating the physical behavior of the model 230 of the portion of thecontinuous web of diaper materials 231 being conveyed over the roller352, during a particular period of time. In another embodiment of thepresent disclosure, the simulation of the fourth step 884 can simulate aphysical behavior of a model 538 or 539 of a diaper trim material 518 or519 interacting with a model of a portion of a trim removal apparatus660 and moving through a model 775 of the air 776, 778, 779, during aparticular period of time.

The method 880 includes a fifth step 885 of evaluating the simulation ofthe fourth step 884. The evaluating can qualitatively and/orquantitatively evaluate any aspect of the physical behavior of any partor parts or some or all of the models being simulated. The evaluatingcan be performed by using computer data, measurements, or analysis,and/or by using information gained by human observation of thesimulation. As an example, the evaluating can determine a particularperiod of time for a physical behavior to occur or not occur in thesimulation. As further examples, the evaluating can evaluate a size,shape, orientation, or any other physical characteristic of any part orparts or some or all of the models being simulated at any time in thesimulation. As still further examples, the evaluating can evaluate aforce, pressure, velocity, or any other physical constraint of any partor parts or some or all of the models being simulated at any time in thesimulation. In some embodiments of a method of simulating a physicalbehavior of a diaper and/or diaper materials in a diaper manufacturingprocess, the fifth step 885 may be omitted.

The method 880 includes a sixth step 886 of modifying one or more of themodels used in the simulation of the fourth step 884. In variousembodiments, the modifying can be based on the evaluation of the fifthstep 885. In some embodiments of a method of simulating a physicalbehavior of a diaper and/or diaper materials in a diaper manufacturingprocess, the sixth step 886 may be omitted.

After the sixth step 886 is performed, the method 880 can be consideredto be complete, or, optionally, some or all of the steps in the method880 can be repeated. In other words, the method 880 can be performed asa single iteration or as multiple iterations. As an example, after thesixth step 886 is performed, the simulation of the fifth step 885 can berepeated, with one or more modified models, in order to evaluate theeffect of any modifications, as will be understood by one of ordinaryskill in the art.

Thus, the present disclosure includes methods of simulating the physicalbehavior of one or more diapers and/or diaper materials interacting withdiaper machines and moving through surrounding air. Embodiments of thepresent disclosure can at least assist in predicting whether or not aparticular diaper machine design can successfully process a particularconfiguration of a diaper and/or diaper materials. As a result,particular diaper machine designs and particular configurations ofdiapers and/or diaper materials can be evaluated and modified ascomputer based models before they are tested as real world things.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm,”

All documents cited in the Detailed Description are, in relevant part,incorporated herein by reference; the citation of any document is not tobe construed as an admission that it is prior art with respect to thepresent invention. To the extent that any meaning or definition of aterm in this document conflicts with any meaning or definition of thesame term in a document incorporated by reference, the meaning ordefinition assigned to that term in this document shall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A method of simulation, comprising: creating a computer based modelof a portion of a continuous web of disposable article material, whereinthe portion of the continuous web of disposable article materialincludes: a sheet-like series of partially formed, connected disposablearticles; and a leading edge with a rigid middle portion, a rigidtrailing edge, and a flexible middle portion held in tension between theleading edge and the rigid trailing edge; creating a computer basedmodel of at least a portion of a disposable article converting machine,wherein the disposable article converting machine is configured toconvert a continuous web of disposable article material into individualdisposable articles, and wherein the portion of the disposable articleconverting machine is configured to physically interact with the portionof the continuous web of disposable article material; and simulating aphysical behavior of the model of the portion of the continuous web ofdisposable article material interacting with the model of the portion ofthe disposable article converting machine, during a particular period oftime.
 2. The method of claim 1, wherein the portion of the continuousweb of disposable article material is a portion of a continuous web ofdiaper material.
 3. The method of claim 2, wherein the portion of thecontinuous web of diaper material includes a sheet-like series ofpartially formed, connected diapers, wherein each of the diapersincludes a chassis and an absorbent core.
 4. The method of claim 3,wherein the portion of the continuous web of diaper material includes asheet-like series of at least four partially formed diapers connectedtogether end-to-end.
 5. The method of claim 1, wherein the portion ofthe continuous web of disposable article material is a portion of acontinuous web of feminine hygiene product material.
 6. The method ofclaim 1, wherein the portion of the continuous web of disposable articlematerial is a portion of a continuous web of paper towel material. 7.The method of claim 1, wherein the portion of the continuous web ofdisposable article material is a portion of a continuous web of bathroomtissue material.
 8. The method of claim 1, wherein the portion of thecontinuous web of disposable article material is a portion of acontinuous web of facial tissue material.
 9. The method of claim 1,wherein the portion of the continuous web of disposable article materialis a portion of a continuous web of wipe material.
 10. The method ofclaim 1, wherein the portion of the continuous web of disposable articlematerial is a portion of a continuous web of cleaning pad material. 11.The method of claim 1, wherein: creating the computer based model of theportion of the disposable article converting machine includes creating acomputer based model of at least a portion of a folding apparatus; andthe simulating includes simulating the physical behavior of the model ofthe portion of the continuous web of disposable article material beingfolded by the model of the folding apparatus, during the particularperiod of time.
 12. The method of claim 11, wherein the creating of thecomputer based model of the portion of the disposable article convertingmachine includes creating a computer based model of at least a portionof a folding apparatus, wherein a contact surface of the foldingapparatus is configured with a coefficient of friction of about 0.1. 13.The method of claim 1, wherein: creating the computer based model of theportion of the disposable article converting machine includes creating acomputer based model of a roller, and the simulating includes simulatingthe physical behavior of the model of the portion of the continuous webof disposable article material being conveyed over the model of theroller, during the particular period of time.
 14. The method of claim13, wherein the creating of the computer based model of the portion ofthe disposable article converting machine includes creating a computerbased model of at least a portion of a roller, wherein a contact surfaceof the roller is configured with a coefficient of friction of about 1.0.15. The method of claim 1, wherein the simulating of the physicalbehavior of the model of the portion of the continuous web of disposablearticle material includes simulating a cutting of the portion of thecontinuous web of disposable article material.
 16. The method of claim1, wherein the simulating of the physical behavior of the model of theportion of the continuous web of disposable article material includessimulating a deforming of the portion of the continuous web ofdisposable article material.
 17. The method of claim 1, wherein thesimulating of the physical behavior of the model of the portion of thecontinuous web of disposable article material includes simulating abonding of the portion of the continuous web of disposable articlematerial.
 18. A computer readable medium having instructions for causinga device to perform a method, the method comprising: creating a computerbased model of a portion of a continuous web of disposable articlematerial, wherein the portion of the continuous web of disposablearticle material includes: a sheet-like series of partially formed,connected disposable articles; and a leading edge with a rigid middleportion, a rigid trailing edge, and a flexible middle portion held intension between the leading edge and the rigid trailing edge; creating acomputer based model of at least a portion of a disposable articleconverting machine, wherein the disposable article converting machine isconfigured to convert a continuous web of disposable article materialinto individual disposable articles, and wherein the portion of thedisposable article converting machine is configured to physicallyinteract with the portion of the continuous web of disposable articlematerial; and simulating a physical behavior of the model of the portionof the continuous web of disposable article material interacting withthe model of the portion of the disposable article converting machine,during a particular period of time.
 19. The computer readable medium ofclaim 18, wherein the portion of the continuous web of disposablearticle material is a portion of a continuous web of diaper material.20. The computer readable medium of claim 18, wherein the portion of thecontinuous web of disposable article material is selected from the groupincluding: a portion of a continuous web of feminine hygiene productmaterial; a portion of a continuous web of paper towel material; aportion of a continuous web of bathroom tissue material; a portion of acontinuous web of facial tissue material; a portion of a continuous webof wipe material; and a portion of a continuous web of cleaning padmaterial.